Efficacy of extraction and incubation of ER and PgR with different solvent systems from rabbit uterus

Methods for improving the estrogen receptor (ER) and progestin receptor (PgR) assay were studied. Using DCC procedure as the basis, the extraction and incubation of ER and PgR is more efficiently achieved by phosphate buffer as compared with water, tris and veronal buffers. The multiple extractions of hormone receptors by any solvent system used is more complete than a single operation of homogenization and centrifugation. The utilization of combined extraction first with water and then phosphate buffer, followed by incubation of the cytosol in phosphate buffer with hormone is also an efficient procedure for the assay of both ER and PgR.